A hollow fiber membrane type artificial lung using porous membranes generally can be used as an extracorporeal circulator or an artificial heart-lung apparatus for assisting circulation in open heart surgery for a heart disease. The hollow fiber membranes can be used for membrane type artificial lungs. Gas exchange in blood is performed through these hollow fiber membranes. As a system of blood flow to the artificial lung, there are an inside flow system in which the blood flows inside of the hollow fiber membranes and gas flows outside of the hollow fiber membranes, and an outside flow system in which, by comparison, the blood flows outside of the hollow fiber membranes and gas flows inside of the hollow fiber membranes.
In hollow fiber membrane type artificial lungs, inner surfaces or outer surfaces of the hollow fiber membranes are in contact with the blood. Therefore, there is a concern that the inner surfaces or the outer surfaces of the hollow fiber membranes in contact with the blood may affect adhesion (attachment) or activation of the platelet system. For example, an outside flow type artificial lung in which the outer surfaces of the hollow fiber membranes are in contact with the blood can generate a blood flow which can cause adhesion (attachment) or activation of the platelet system.
Considering such problems, and in view of the suppression and prevention effects of alkoxyalkyl (meth)acrylate on adhesion or activation of the platelet system, as antithrombotic material, alkoxyalkyl (meth)acrylate can be used for coating the hollow fiber membranes of an outside flow type artificial lung. For example, U.S. Pat. No. 6,495,101 B1 (corresponding to JP-A-11-114056 and EP 0 908 191 A1) discloses that outside surfaces or outer surface layers of the hollow fiber membranes are coated with a coating solution obtained by dissolving a polymer containing alkoxyalkyl (meth)acrylate as a main component in a mixed solvent of water, methanol, and ethanol, and then dried.